I had not published them before since I am not sure if these options are optimal for all cases or not. Anyway I am providing them as it looks it will help lot of people to jumpstart with Postgres on Solaris and in the meanwhile I can continue doing more tests and tweak them for another entry if required.

The PostgreSQL binaries were configured with Sun Studio 12 as follows:

The actual database was divided into three file systems: One for $PGDATA, one for pg_xlog and one more for index tablespaces. All mounted with forcedirectio option)Your mileage may vary but hopefully for the better.